Since the first Sensory Integration International (SII) training course in Ireland in 1990, occupational therapists have come to use this model of practice in planning and implementing treatment with a wide range of clients—premature babies, adults with learning disability, special schools for physical or learning disabilities, child and adolescent psychiatry, and in community services. Smaller numbers of physiotherapists and speech and language therapists have also undertaken postgraduate training in this theory and remediation approach. Mulcahy (1994) researched the use of sensory integration in clinical settings in Ireland and noted a steady increase in the use of SI with children with learning disability. Further foundation courses have been held in Ireland and the UK. Some recently-advertised paediatric occupational therapy posts have specified sensory integrative training as a prerequisite for the job, thus highlighting the relevance of this approach in occupational therapy service delivery today. The ‘Sensory Integration Network’ has linked the use of the theory and treatment model in Ireland and the UK and is involved in standardising the postgraduate training of therapists and coordinating the use of this valuable approach.
Wherever occupational therapists work, their major goal is to enhance the individual’s occupational performance, to enable them to interact with the environment in a meaningful and competent manner. Sensory integration is the organisation of sensory input for use. The many parts of the nervous system work together so that the individual can interact with the environment effectively. Dysfunction of the sensory system affects one’s ability to regulate activity levels and negatively affects the development of precise skilled motor control, which in turn affects one’s occupational performance in the areas of self-care, productivity and leisure.
Therapists trained in sensory integration refer to the ‘hidden’(proprioceptive and vestibular) senses, as well as the traditional senses of touch, taste, smell, sight and sound. The vestibular and proprioceptive senses give us valuable information about movement and gravity, as well as awareness of body position. Massive amounts of sensory information are relayed discretely and subconsciously to our brain throughout our working day. One of the most important tasks for our brain is to sort and inhibit unnecessary sensory information. For example, when we dress in the morning our sense of touch tells us about the texture of the garment and how much of our body it covers. However, it is not necessary for us to be constantly reminded throughout the day of the sensory properties of our clothing. The brain therefore inhibits this information, and in so doing frees our minds for engagement in more cognitively challenging pursuits.
Sensory integration theory attempts to explain the problems in learning and behaviour in children, especially those associated with motor in-coordination and poor sensory processing, that cannot be attributed to frank central nervous system damage or abnormalities (Fisher et al. 1991). The theory is not intended to explain the learning difficulties and neuromotor deficits associated with such problems as cerebral palsy (eg. abnormal muscle tone), Down Syndrome (eg. low intellectual functioning) or stroke (eg. decreased tactile discrimination). However, individuals with learning disabilities attributable to central nervous system damage or abnormalities may have additional deficits in sensory integration, and in such circumstances the application of sensory integration theory would be valid as part of an overall treatment plan (Chu & Green 1996).
Sensory experience is essential to the developing brain. When people have atypical sensory experience, either because of their own internal processing of sensory stimulation or external environmental factors, there is always a disturbance in their behaviour and performance. Durrand and Carr (1985) list sensory consequences as one of the four motivating conditions that relate to self-injurious behaviour. They suggest that self injury in some instances may be maintained by sensory rather than (or in addition to) social consequences. Sensory integrative dysfunction is thought to be a significant but undetected problem for many individuals with learning disabilities (Reisman 1993). The aim of the sensory integrative treatment programme is to enable the individual with learning disabilities to process sensory information more effectively, in order to cope more successfully with reasonable environmental demands in their occupational performance areas, ie. self-care, productivity and leisure.
Disturbances of sensory processing have been reported in research for more than twenty years, supporting the sensory integrative approach as a valuable therapeutic tool (Ayres & Tickle 1980). Individuals with autism frequently withdraw from their environment and the people in it, in order to block out the onslaught of incoming stimulation. They may be over-reactive to smells, movement, sounds and other sensory stimuli. Gorman (1997) suggests that over-reactive individuals, when overwhelmed with sensory stimuli, may engage in stereotyped behaviours to help calm their over-aroused nervous systems. These difficulties with sensory processing are not exclusive to autism; the inability to respond appropriately (in a graded manner) to sensory stimuli is a problem for many people with learning disabilities and is referred to as a ‘sensory modulation disorder’. The individual who is unable to grade or dampen-down his/her responses may over-react and present as anxious, distractible and fragmented (with no ‘off’ button).
Sensory modulation is an important aspect of self-regulation, eg. mastery of sleep/wake cycles, the ability to cope with and accept changes in routine, hunger/satiety, self-calming, mastery of sensory functions and regulation of attention and arousal. An inability to modulate sensory information interferes with the ability to produce adaptive environmental interactions and may present in either of the following ways:
- The individual who over-responds in a manner disproportional to the input (Fisher et al. 1991) is in a continuous ‘fight or flight’ state. They must respond to all stimuli and consequently feel high levels of anxiety, often presenting with erratic/rapid breathing, clammy hands, etc. Sensory avoidance behaviours may be observed, eg. sitting in a corner, needing large personal space or adopting self-selected calming techniques.
- The individual who under-responds or experiences sensory dormancy. In this instance the person may need large amounts of stimulation to achieve a state of arousal. He/she may show delay in responding to movement, touch or pain and appear to ignore/reject objects in their environment.
Recent literature would indicate that under-reactions and over-reactions are not mutually exclusive. The individual with a sensory modulation disorder may be on a continuum of hyporeactive and hyperreactive responses (Fisher et al. 1991). This may be likened to a ‘seesaw’, where the individual shifts quickly from one extreme to the other without being in the mid-range or normal reactive phase (Royeen 1989). Such people cannot readily engage with their environment—whether in a Romanian orphanage, a state-of-the-art residential facility, a comfortable family home, or indeed one of the many multisensory environments that are now found in many progressive centres.
The most significant and appropriate activities for us all are those that are self-initiated and purposeful. Sensory integration capitalises on this; it is a client-centred approach, tapping into the individual’s ‘inner drive’ or motivation to meet the challenges of his/her environment. Occupational therapists can help individuals to get the most out of purposeful activity by assisting them to modulate sensory input, ie. to change their response from fear and/or avoidance to pleasure and exploration. The right combination of sensory input, an optimal level of arousal, and being challenged at just the right level enhances the individual’s occupational performance.
Wilbarger (1995) coined the term ‘sensory diet’ to explain that we all have unique sensory needs; sensory stimulation is like food for the brain. Our sensory diet, like our nutritional diet, needs just the right combinations of sensory input to adequately nourish us. The primary purpose of a therapeutic sensory diet is important for any person, but especially for those with a disruption in sensory experiences due to a disorder of sensory processing or a decreased ability to engage in activity.
A sensory diet can be incorporated into all aspects of daily life and within any setting. The occupational therapist works with the primary carers in structuring the sensory diet, which would ideally contain specific time-oriented routines, adaptations and changes in set routines, a structured environment and the use of selected equipment. Typical development does not occur without a certain amount of sensory experience; the successful integration of these experiences is essential in the development of a well-integrated adaptive individual.
Sensory integration is currently the most researched model in occupational therapy. It is a valuable tool with which to address deficits in clients’ occupational performance. This article has primarily explored the use of sensory integration with those who are unable to appropriately modulate their responses to sensory inputs. The approach is equally applicable to clients with minimal learning disability, those whose subtle sensory deficits limit their ability to effectively direct their movements (writing, cutting, typing laces), rather than because of a primary cognitive deficit.